Win 7 Desktop became bluish (not BSoD) when mouse is released (& possibly Ctrl key pressed)

Quite often after moving the mouse & my right hand let go of the mouse (& possibly I may
have pressed Ctrl key), the Desktop will become bluish as shown in attached.

I'm not exactly sure what I pressed (as I can't consistently reproduce this) that bring up
this disruptive bluish desktop.  To recover from it, I just move the mouse & click on the
Desktop & it will recover.

Not sure if it's related but currently when I pressed the fullstop ie the . key which is also
the key/button with > on it), it will often activate a key below it: it's the key between the
right Alt & right Ctrl keys on my Thinkpad X220 keypad) & this will bring up a little menu:
refer to attachment 2's screen (in a browser, while typing the . key, it will pop up a menu
with Undo, Redo, ...).   Our laptop support guys gave me a USB keyboard to use & it seems
to help so far while reinstalling the entire Windows 7 did not help so we're inclined to
believe it's a keypad hardware issue as the . key was just right above that key (I can take a
 photo of that key if needed; I dont know what's that key called).

Let's resolve the disruptive bluish screen first as our IT guys are going to order a spare
keypad for my X220 later.

This very same Logitech Darkfield Anywhere mouse did not trigger this bluish desktop
 issue when used on another Windows 7 PC
BluescrDesktop-Mousemove.jpg
keypadissue1.jpg